\begin{tikzpicture}
    \tkzDefPoints{0/0/A, 4/0/C}
    \tkzDefTriangle[two angles=30 and 90](A,C)  \tkzGetPoint{B}
    \tkzDefLine[bisector](B,A,C)  \tkzGetPoint{a}
    \tkzDefLine[bisector](C,B,A)  \tkzGetPoint{b}
    \tkzInterLL(A,a)(B,b)  \tkzGetPoint{I}
    \tkzDefLine[altitude](B,I,C)  \tkzGetPoint{D}
    \tkzDefLine[altitude](C,I,A)  \tkzGetPoint{E}
    \tkzDefLine[altitude](A,I,B)  \tkzGetPoint{F}

    \tkzDrawPolygon(A,B,C)
    \tkzDrawCircle[thick](I,D)
    \tkzDrawSegments(I,D  I,E)
    \tkzMarkRightAngle[size=.2](B,C,A)

    \tkzLabelPoints[below](A,C,E)
    \tkzLabelPoints[left](I)
    \tkzLabelPoints[right](B,D)
    \tkzLabelPoints[below](E)
    \tkzLabelPoints[left, yshift=.5em](F)
\end{tikzpicture}

